It seems that you still have some fitness knowledge. (* _ _ *) Abdominal muscles are a symbol of strength and armor to protect important parts of the body. Abdominal muscle weakness may lead to pelvic forward tilt and increase the physiological curvature of lumbar spine, increasing the chance of low back pain. It is very necessary to practice abdominal muscles. The following are three groups of abdominal exercises, which are simple and classic: supine leg lifting. Lie flat on the bed or mat, with your back close to the bed surface (or ground), hold the head of the bed with both hands to fix the upper body, and lift and put down your legs at the same time, repeatedly. Pay attention to the action: 1. The body is easy to shake, so you can find a partner to resist the upper body to prevent the body from shaking. 2. If you want to exercise the lower abdomen to the maximum extent, you should try to lift your hips at the highest point of each movement to fully mobilize the muscles of the lower abdomen. 3. If you think this action is difficult, you can bend your legs slightly to reduce the difficulty and complete the action. Lie on your back, lift your legs and pedal. Lie flat on the bed or mat, with your back close to the bed surface (or ground); At the same time, lift your legs high, let your legs stay in the air, and do the action of pedaling your bike in the air, repeatedly. Pay attention when doing the action: 1. You will feel very tired when you do this action for the first time. The amplitude should not be too large and the speed should not be too fast. 2. After you have mastered the movements, you can increase the exercise intensity by straightening your legs every time you "pedal". Sit-ups Lie flat on the ground, put your calves on the bench (or chair, edge of bed, steps), and use the strength of abdominal muscles to make your upper body sit up straight. When recovering, the shoulders slowly fell back to the ground, and the abdominal muscles were always tight. Pay attention to this action: 1. Don't put your hands behind your head. Because when you are exhausted, you will put your head in your hands, which will damage your neck muscles. 2. The higher the shoulder is from the ground, the straighter the better, but the waist should stick to the ground. 3. Pay attention to the stability of the upper body. 4. Don't kick your feet.